Surprise, Arizona: planting zone & frost dates
Surprise is in USDA plant hardiness zone 9b, where the average coldest winter night reaches 25 to 30°F (-3.9 to -1.1°C). The typical last spring frost is around Feb 16 and the first fall frost around Dec 2.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Mar 3 | Nov 20 |
| Typical planning date (30% risk) | Feb 16 | Dec 2 |
| Median (50%) | Feb 5 | Dec 11 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station WITTMANN 1SE, AZ (USC00029464), 8.4 mi (13.5 km) from the city center and 322 ft higher than the city center (+98 m). Record used for the 1991–2020 normals: 20 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Surprise
All 8 ZIP codes covering Surprise are in zone 9b.
Vegetable planting calendar for Surprise
Dates are counted from the 30%-risk frost dates above (last frost Feb 16, first frost Dec 2). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Dec 22 – Jan 5 | Feb 23 – Mar 9 | — | — |
| Pepper | Dec 8 – Dec 22 | Mar 2 – Mar 16 | — | — |
| Lettuce Mild winters: fall and winter plantings are usually more reliable than spring. | Jan 5 – Jan 19 | Feb 2 – Feb 23 | Jan 19 – Mar 2 | Sep 23 – Oct 21 |
| Green Beans | — | — | Feb 23 – Mar 30 | Sep 9 – Sep 23 |
| Sweet Corn | — | — | Feb 23 – Mar 23 | — |
| Zucchini & Summer Squash | Jan 19 – Jan 26 | Feb 23 – Mar 9 | Feb 23 – Mar 16 | Sep 9 – Sep 23 |
| Cucumber | Jan 19 – Jan 26 | Mar 2 – Mar 9 | Feb 23 – Mar 16 | Sep 9 – Sep 23 |
| Carrot Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 26 – Mar 2 | Sep 9 – Sep 23 |
| Onion Mild winters: fall and winter plantings are usually more reliable than spring. | Nov 24 – Dec 8 | Jan 19 – Feb 2 | — | — |
| Potato Mild winters: fall and winter plantings are usually more reliable than spring. | — | Jan 19 – Feb 9 | — | — |
| Basil | Jan 5 – Jan 19 | Mar 2 – Mar 16 | Mar 2 – Mar 23 | — |
| Spinach Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 5 – Feb 2 | Oct 7 – Nov 4 |
| Kale Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 22 – Jan 5 | Jan 19 – Feb 9 | Jan 19 – Feb 9 | Sep 23 – Oct 21 |
| Broccoli Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 22 – Jan 5 | Feb 2 – Feb 23 | — | Sep 9 – Sep 23 |
| Peas Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 5 – Jan 26 | Sep 23 – Oct 7 |
| Eggplant | Dec 8 – Dec 22 | Mar 2 – Mar 16 | — | — |
| Cabbage Mild winters: fall and winter plantings are usually more reliable than spring. | Dec 22 – Jan 5 | Jan 19 – Feb 2 | — | Sep 9 – Sep 23 |
| Radish Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 12 – Mar 2 | Oct 21 – Nov 18 |
| Strawberry | — | Jan 19 – Feb 9 | — | — |
| Beets Mild winters: fall and winter plantings are usually more reliable than spring. | — | — | Jan 26 – Mar 9 | Sep 23 – Oct 7 |
Nearby cities in Arizona
- Peoria — zone 9b, last frost Feb 16, first frost Dec 2
- Avondale — zone 9b, last frost Jan 18, first frost Dec 16
- Glendale — zone 9b, last frost Feb 2, first frost Dec 8
- Buckeye — zone 9b, last frost Jan 18, first frost Dec 16
- Phoenix — zone 9b, last frost Jan 23, first frost Dec 15
- Goodyear — zone 9b, last frost Jan 29, first frost Dec 12
More: all Arizona cities · other zone 9b cities: Houston, TX, Phoenix, AZ, Jacksonville, FL, San Jose, CA, Fresno, CA, Sacramento, CA, Mesa, AZ, Bakersfield, CA
Surprise gardening questions
When is the last frost in Surprise, AZ?
Plan around Feb 16. At NOAA's Wittmann 1SE, AZ station, 8.4 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Feb 5, and after Mar 3 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Jan 15. Springs here are erratic: 56 days separate the 90% and 10% dates, versus a median of 36 days for cities on this site, so watch the forecast rather than the calendar.
When should I plant tomatoes in Surprise, AZ?
Start seeds indoors Dec 22 – Jan 5 and set transplants outside Feb 23 – Mar 9, once nights stay above 50°F and the soil is near 60°F. With about 289 frost-free days, frost is not the main limit — fruit set drops when nights stay above about 75°F, so early plantings tend to do best. More: tomato planting dates by zone.
How long is the growing season in Surprise?
About 306 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 270 days, and in 1 year in 10 it runs 341 days or more. In fall there is a 10% chance of frost by Nov 20 and a 30% chance by Dec 2. That ranks 12th longest of 16 Arizona cities on this site.
When should I plant a fall garden in Surprise?
Count back from the first fall frost (Dec 2): transplant broccoli Sep 9 – Sep 23; sow kale Sep 23 – Oct 21; sow lettuce Sep 23 – Oct 21; sow radishes Oct 21 – Nov 18. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Dec 27. How the math works: succession and fall planting.
Did Surprise's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Surprise is zone 9b on both the 2012 and the 2023 USDA maps (PRISM/OSU ZIP listings). About 42% of U.S. ZIP codes kept their half-zone in 2023. Why the 2023 map is warmer.
How does Surprise compare with Avondale, AZ?
Both are in zone 9b. The typical last spring frost in Surprise (Feb 16) comes about 29 days later than in Avondale, AZ (Jan 18), 17 miles away, and the first fall frost is Dec 2 versus Dec 16. Surprise sits about 390 ft higher, which explains part of the gap. The two cities use different NOAA stations.